Great improvements in oil recovery are necessary to satisfy the present and future energy requirements of the United States. Thus, improvements are needed in the field of enhanced thermal recovery, such as an improved in situ combustion ignition system for use in heavy oils, tar sands, and oil shale, particularly in deep wells.
Various types of ignition systems have been used and are in use for in situ combustion ignition. Electrical heaters have been used extensively but are limited to 3000 ft or less due to the problem of supplying adequate electrical power to greater depths. The use of gas burning ignition systems becomes more difficult with depth because most designs include a multiplicity of air and gas conduits and electrical cables which complexes the placement of the systems as the depth becomes greater. A recently developed catalytic heater utilizes only a wireline for placement, but has the disadvantage of operating without a temperature monitoring system. Some gas ignition systems have the disadvantage of requiring complete removal from the well and re-running if flameout occurs. This becomes very expensive in rig time alone.